YM2612
| Manufacturer | Yamaha |
|---|---|
| Code | OPN2 (OPN series) |
| Type | FM, PCM |
| Channels | 6 (5 FM, 1 FM/DAC) |
| Package | DIP24 0.7" |
| Produced | 198X-199X |
| Variants | YM3438, SEGA VDP YM3438, YMF276 |
| Clones | PCS8593, SE-95, TA-07 |
The YM2612, or OPN2, is an FM chip produced by Yamaha, best known for its use in the SEGA Mega Drive game console.
Variants
YM3438
The YM3438 (OPN2C) is a variant of the YM2612 using CMOS technology. While pin-compatible, it requires different surrounding analog circuitry. There are also differences in the timer behavior which prevent it from being a drop-in replacement for the original chip. DAC output quality is significantly improved compared to the YM2612.
The YM3438 is used in the following devices:
- Fujitsu FM Towns computers
- SEGA System 32 and UFO catcher arcade boards
SEGA VDP YM3438
While the original Mega Drive used a discrete YM2612 chip, later versions of the console integrated its functionality into the VDP. This version is similar to the discrete YM3438, but retains the original YM2612 timer behavior to ensure compatibility with existing software.
YMF276
Another official variant known as the YMF276 (OPN2L) was produced for later FM Towns computers. In contrast to the other variants, the YMF276 eschews the internal DAC in favor of a serial digital audio output. It is also the only OPN2 variant to use a surface mount package.
Clones
The popularity of the Mega Drive led to this chip being cloned for use in bootleg consoles.